U.S. patent application number 11/525053 was filed with the patent office on 2007-11-15 for relay apparatus, relay method, relay program, and communication system.
This patent application is currently assigned to FUJITSU LIMITED. Invention is credited to Ryuichi Matsukura, Motoshi Sumioka, Hitoshi Yamauchi.
Application Number | 20070263818 11/525053 |
Document ID | / |
Family ID | 38222390 |
Filed Date | 2007-11-15 |
United States Patent
Application |
20070263818 |
Kind Code |
A1 |
Sumioka; Motoshi ; et
al. |
November 15, 2007 |
Relay apparatus, relay method, relay program, and communication
system
Abstract
A relay apparatus for relaying communication between a plurality
of wireless terminals and a wired network includes a priority data
recording part for recording communication identification data and
required bandwidth data, a priority control part for relaying, by
priority, the communication recorded in the priority data recording
part, a request receiving part for receiving communication
identification data and multimedia type data, a selecting part for
selecting a multimedia type to be relayed by priority, an updating
part for additionally recording data that represents a bandwidth
required for relaying a stream of the selected multimedia type and
the communication identification data, and a responding part for
transmitting a response. The selecting part selects the multimedia
type so that a sum of bandwidths represented by the required
bandwidth data does not exceed a predetermined upper limit value.
With the above configuration, the relay apparatus can perform
bandwidth control of communication to be relayed, considering the
multimedia type included in the communication by a wireless
terminal.
Inventors: |
Sumioka; Motoshi; (Kawasaki,
JP) ; Matsukura; Ryuichi; (Kawasaki, JP) ;
Yamauchi; Hitoshi; (Kawasaki, JP) |
Correspondence
Address: |
STAAS & HALSEY LLP
SUITE 700, 1201 NEW YORK AVENUE, N.W.
WASHINGTON
DC
20005
US
|
Assignee: |
FUJITSU LIMITED
Kawasaki
JP
|
Family ID: |
38222390 |
Appl. No.: |
11/525053 |
Filed: |
September 22, 2006 |
Current U.S.
Class: |
379/201.01 |
Current CPC
Class: |
H04L 65/4084 20130101;
H04L 29/06027 20130101; H04L 65/80 20130101; H04L 47/14 20130101;
H04L 65/4076 20130101; H04L 65/1083 20130101; H04L 47/10 20130101;
H04L 47/2433 20130101; H04L 47/2416 20130101; H04W 28/02
20130101 |
Class at
Publication: |
379/201.01 |
International
Class: |
H04M 3/42 20060101
H04M003/42 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 31, 2006 |
JP |
2006-100277 |
Claims
1. A relay apparatus of the present invention for relaying
communication between a plurality of wireless terminals and a wired
network, includes: a wireless communication part for enabling
wireless communication between the plurality of wireless terminals
and the relay apparatus; a wired network connecting part for
connecting the relay apparatus and the wired network including a
communication control apparatus that controls starting and ending
of communication between the wireless terminals; a priority data
recording part for recording communication identification data that
represents a prioritized communication to be relayed by priority
and required bandwidth data that represents a quantity of the
transport bandwidth required by the prioritized communication; a
priority control part for relaying the prioritized communication by
priority compared with the others based on the communication
identification data recorded in the priority data recording part; a
request receiving part for receiving, from the wireless terminal, a
request message that contains communication identification data
representing a starting communication and multimedia type data
representing one or more multimedia types of the streaming
communication contained within the starting communication; a
selecting part for selecting at least one multimedia type of the
streaming communication contained within the starting
communication, referring the required bandwidth data recorded in
the priority data recording part and data representing bandwidth
required for relaying each streaming communication calculated by
the multimedia type data; an updating part for updating the data
which is recorded in the priority data recording part, newly adding
data representing a quantity of bandwidth for relaying the
streaming communication whose multimedia type is selected by the
selecting part and the communication identification data
representing a starting communication; a responding part for
transmitting data that represents the streaming communication to be
relayed by priority, selected by the selecting part, to the
communication control apparatus, as a response to the request
message, wherein the selecting part selects the multimedia type of
the each streaming communication contained within the starting
communication not to exceed a predetermined upper limit of the
total value of bandwidth required for relaying the prioritized
communication even if adding the required bandwidth for relaying
the starting communication.
2. The relay apparatus according to claim 1, further comprising a
precedence recording part that records a precedence of a plurality
of multimedia types, wherein the selecting part selects at least
one multimedia type of the streaming communication to be relayed by
priority based on the precedence recorded in the precedence
recording part.
3. The relay apparatus according to claim 1, wherein the selecting
part requests the communication control apparatus to inquire of a
wireless terminal that requests starting of communication about a
multimedia type of a streaming communication to be relayed by
priority, obtains data that represents the multimedia type of the
streaming communication to be relayed by priority as a response to
the request from the communication control apparatus, and selects
the multimedia type of the streaming communication based on the
obtained data.
4. A relay apparatus for relaying communication between a plurality
of wireless terminals and a wired network, comprising: a wireless
communication part for enabling wireless communication between the
plurality of wireless terminals and the relay apparatus; a wired
network connecting part for connecting the relay apparatus and the
wired network including a communication control apparatus that
controls start and ending of communication of the wireless
terminals; a plurality of priority grade data recording parts for
recording stream identification data for identifying a streaming
communication to be relayed by priority with respect to each stage
of priority provided in a plurality of stages; a precedence
recording part for recording precedence of a plurality of
multimedia types; a priority control part for relaying a streaming
communication specified by the stream identification data recorded
in the priority grade data recording part with higher priority, by
priority compared with a streaming communication specified by the
stream identification data recorded in the priority grade data
recording part with lower priority; a request receiving part for
receiving a request message containing the communication
identification data that represents a starting communication of a
wireless terminal ready to be started and multimedia type data that
represents each multimedia type of one or a plurality of streaming
communications included in the starting communication; a priority
determining part for determining priority with respect to a
streaming communication of each multimedia type represented by the
multimedia type data, based on the precedence recorded in the
precedence recording part; and an updating part for recording the
stream identification data for identifying the streaming
communication specified by the communication identification data
and the multimedia type data in the priority grade data recording
part in accordance with the priority determined by the priority
determining part, with respect to the streaming communication of
each multimedia type.
5. A communication system accessible wirelessly from a plurality of
wireless terminals, comprising: a relay apparatus for relaying
communication between a wired network and the plurality of wireless
terminals, and a communication control apparatus connected to the
relay apparatus via the wired network, wherein the communication
control apparatus includes: an interconnecting part for
transmitting a request message that contains communication
identification data representing a starting communication and
multimedia type data representing one or more multimedia types of
the streaming communication contained within the starting
communication, based on a request for starting of communication
received from an arbitrary wireless terminal; and a communication
control part for receiving a response to the request message
transmitted by the interconnecting part from the relay apparatus,
and controlling the starting of communication for each streaming
communication included in the starting communication based on the
response, wherein the relay apparatus includes: a priority data
recording part for recording communication identification data that
represents a prioritized communication to be relayed by priority
and the required bandwidth data that represents a quantity of the
transport bandwidth required by the prioritized communication; a
priority control part for relaying the prioritized communication by
priority compared with the others based on the communication
identification data recorded in the priority data recording part; a
request receiving part for receiving, from the wireless terminal, a
request message that contains communication identification data
representing a starting communication and multimedia type data
representing one or more multimedia types of the streaming
communication contained within the starting communication; a
selecting part for selecting at least one multimedia type of the
streaming communication contained within the starting
communication, referring the required bandwidth data recorded in
the priority data recording part and data representing bandwidth
required for relaying each streaming communication calculated by
the multimedia type data; an updating part for updating the data
which is recorded in the priority data recording part, newly adding
data representing a quantity of bandwidth for relaying the
streaming communication whose multimedia type is selected by the
selecting part and the communication identification data
representing a starting communication; a responding part for
transmitting data that represents the streaming communication to be
relayed by priority, selected by the selecting part, to the
communication control apparatus, as a response to the request
message, wherein the selecting part selects the multimedia type of
the each streaming communication contained within the starting
communication not to exceed a predetermined upper limit of the
total value of bandwidth required for relaying the prioritized
communication even if adding the required bandwidth for relaying
the starting communication.
6. A relay method for a relay apparatus to relay communication
between a plurality of wireless terminals and a wired network, the
relay apparatus including: a wireless communication part for
enabling wireless communication between the plurality of wireless
terminals and the relay apparatus; a wired network connecting part
for connecting the relay apparatus and the wired network including
a communication control apparatus that controls starting and ending
of communication between the wireless terminals; and a priority
data recording part for recording communication identification data
that represents a prioritized communication to be relayed by
priority and required bandwidth data that represents a quantity of
the transport bandwidth required by the prioritized communication,
the method includes: a request receiving operation of receiving,
from the wireless terminal, a request message that contains
communication identification data representing a starting
communication and multimedia type data representing one or more
multimedia types of the streaming communication contained within
the starting communication; a selecting operation of selecting at
least one multimedia type of the streaming communication contained
within the starting communication, by referring the required
bandwidth data recorded in the priority data recording part and
data representing bandwidth required for relaying each streaming
communication calculated by the multimedia type data; an updating
operation of updating the data which is recorded in the priority
data recording part, by newly adding data representing a quantity
of bandwidth for relaying the streaming communication whose
multimedia type is selected by the selecting operation and the
communication identification data representing a starting
communication; and a responding operation of transmitting data that
represents the streaming communication to be relayed by priority,
selected by the selecting operation, to the communication control
apparatus, as a response to the request message, wherein the
selecting operation, the multimedia type of the each streaming
communication contained within the starting communication is
selected not to exceed a predetermined upper limit of the total
value of bandwidth required for relaying the prioritized
communication even if adding the required bandwidth for relaying
the starting communication.
7. A relay program stored in a recording medium for causing a
computer to execute processing of relaying communication between a
plurality of wireless terminals and a wired network, the computer
including: a wireless communication part for enabling wireless
communication between the plurality of wireless terminals and the
computer; a wired network connecting part for connecting the
computer and the wired network including a communication control
apparatus that controls starting and ending of communication
between the wireless terminals; and a priority data recording part
for recording communication identification data that represents a
prioritized communication to be relayed by priority and required
bandwidth data that represents a quantity of the transport
bandwidth required by the prioritized communication, the program
causes the computer to execute: request receiving processing of
receiving, from the wireless terminal, a request message that
contains communication identification data representing a starting
communication and multimedia type data representing one or more
multimedia types of the streaming communication contained within
the starting communication; selecting processing of selecting at
least one multimedia type of the streaming communication contained
within the starting communication, by referring the required
bandwidth data recorded in the priority data recording part and
data representing bandwidth required for relaying each streaming
communication calculated by the multimedia type data; updating
processing of updating the data which is recorded in the priority
data recording part, by newly adding data representing a quantity
of bandwidth for relaying the streaming communication whose
multimedia type is selected by the selecting processing and the
communication identification data representing a starting
communication; and responding processing of transmitting data that
represents the streaming communication to be relayed by priority,
selected by the selecting processing, to the communication control
apparatus, as a response to the request message, wherein the
selecting processing, the multimedia type of the each streaming
communication contained within the starting communication is
selected not to exceed a predetermined upper limit of the total
value of bandwidth required for relaying the prioritized
communication even if adding the required bandwidth for relaying
the starting communication.
8. A relay method for a relay apparatus to relay communication
between a plurality of wireless terminals and a wired network, the
relay apparatus including: a wireless communication part for
enabling wireless communication between the plurality of wireless
terminals and the relay apparatus; a wired network connecting part
for connecting the relay apparatus and the wired network including
a communication control apparatus that controls starting and ending
of communication of the wireless terminals; a plurality of priority
grade data recording parts for recording stream identification data
for identifying a streaming communication to be relayed by priority
with respect to each stage of priority provided in a plurality of
stages; and a precedence recording part for recording precedence of
a plurality of multimedia types, the method comprising: a priority
control operation of relaying a streaming communication specified
by the stream identification data recorded in the priority grade
data recording part with higher priority, by priority compared with
a streaming communication specified by the stream identification
data recorded in the priority grade data recording part with lower
priority; a request receiving operation of receiving a request
message containing the communication identification data that
represents a starting communication of a wireless terminal ready to
be started and multimedia type data that represents each multimedia
type of one or a plurality of streaming communications included in
the starting communication; a priority determining operation of
determining priority with respect to a streaming communication of
each multimedia type represented by the multimedia type data, based
on the precedence recorded in the precedence recording part; and an
updating operation of recording the stream identification data for
identifying the streaming communication specified by the
communication identification data and the multimedia type data in
the priority grade data recording part in accordance with the
priority determined by the priority determining operation, with
respect to the streaming communication of each multimedia type.
9. A relay program stored in a recording medium for causing a
computer to execute processing of relaying communication between a
plurality of wireless terminals and a wired network, the computer
including: a wireless communication part for enabling wireless
communication between the plurality of wireless terminals and the
computer; a wired network connecting part for connecting the
computer and the wired network including a communication control
apparatus that controls starting and ending of communication of the
wireless terminals; a plurality of priority grade data recording
parts for recording stream identification data for identifying a
streaming communication to be relayed by priority with respect to
each stage of priority provided in a plurality of stages; and a
precedence recording part for recording precedence of a plurality
of multimedia types, the program causes the computer to execute:
priority control processing of relaying a stream specified by the
stream identification data recorded in the priority grade data
recording part with higher priority, by priority compared with a
stream specified by the stream identification data recorded in the
priority grade data recording part with lower priority; request
receiving processing of receiving a request message containing the
communication identification data that represents a starting
communication of a wireless terminal ready to be started and
multimedia type data that represents each multimedia type of one or
a plurality of streaming communications included in the starting
communication; priority determining processing of determining
priority with respect to a streaming communication of each
multimedia type represented by the multimedia type data, based on
the precedence recorded in the precedence recording part; and
updating processing of recording the stream identification data for
identifying the streaming communication specified by the
communication identification data and the multimedia type data in
the priority grade data recording part in accordance with the
priority determined in the priority determining processing, with
respect to the streaming communication of each multimedia type.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a relay apparatus for
relaying communication between wireless terminals and a wired
network, and in particular, to a relay apparatus, a relay method,
and a relay program for ensuring the quality of communication to be
relayed, and a communication system including the relay
apparatus.
[0003] 2. Description of Related Art
[0004] Recently, for example, as in an IP telephone via a wireless
LAN, a mobile terminal that performs a telephone conversion via
wireless communication has become widespread. The mobile terminal
that performs a telephone conversation via wireless communication
enables a telephone conversation with a wired network by performing
wireless communication with a relay apparatus (e.g., an access
point of a wireless LAN, etc.). In such a communication form,
mobile terminals are present in a communication area of a relay
apparatus, whereby simultaneous telephone conversations by the
mobile terminals occur. In this case, those mobile terminals share
a communication bandwidth available in the relay apparatus, and
perform communication respectively. Therefore, in the case where
the number of mobile terminals that perform telephone conversations
simultaneously via one relay apparatus increases, the communication
bandwidth becomes insufficient. Consequently, at a mobile terminal,
delays in audio communication from a terminal on a partner side is
increased, and a noise such as a sound break occurs. This problem
may occur in the case of communicating data such as music or a
moving picture by streaming, as well as in the case of a telephone
conversation. In General, the realtime communication to transmit
streaming data as in a IP telephony service, a music distribution,
a movie distribution, and the like, the shortage of a communication
bandwidth in the relay apparatus degrades communication
quality.
[0005] In order to prevent the shortage of a communication
bandwidth in a relay apparatus, for example, a method has been
adopted for rejecting the starting of a telephone conversation via
the relay apparatus when the amount of a communication bandwidth
available in the relay apparatus is not sufficient. Furthermore, a
method has also been proposed, in which a call control apparatus
receives traffic information from a relay apparatus at a constant
interval, and controls the acceptance/rejection of communication to
be relayed by the relay apparatus based on the received traffic
information (e.g., see JP 2003-284144 A). The call control
apparatus restrained making a new call to be relayed by the relay
apparatus consuming large amount of traffic bandwidth when the
usable bandwidth is already full.
[0006] However, in the above-mentioned conventional example, a
multimedia type included in communication to be relayed by the
relay apparatus has not been considered. Therefore, even in the
multimedia communication which contains both audio and video
streams, the relay apparatus was not able to perform a relay
considering multimedia types (e.g., a preferential relay only for
an audio stream). Because recent wireless terminals can handle
multimedia communications, such relay apparatus should consider
those multimedia types.
SUMMARY OF THE INVENTION
[0007] Therefore, there is a demand for a bandwidth control of a
relay apparatus considering a multimedia type included in
communication. The object of the present invention is to provide a
relay apparatus, a relay method, a relay program, and a
communication system capable of controlling a bandwidth of
communication to be relayed, considering a multimedia type included
in the communication by a wireless terminal.
[0008] A relay apparatus of the present invention for relaying
communication between a plurality of wireless terminals and a wired
network, includes: a wireless communication part for enabling
wireless communication between the plurality of wireless terminals
and the relay apparatus; a wired network connecting part for
connecting the relay apparatus and the wired network including a
communication control apparatus that controls starting and ending
of communication between the wireless terminals; a priority data
recording part for recording communication identification data that
represents a prioritized communication to be relayed by priority
and required bandwidth data that represents a quantity of the
transport bandwidth required by the prioritized communication; a
priority control part for relaying the prioritized communication by
priority compared with the others based on the communication
identification data recorded in the priority data recording part; a
request receiving part for receiving, from the wireless terminal, a
request message that contains communication identification data
representing a starting communication and multimedia type data
representing one or more multimedia types of the streaming
communication contained within the starting communication; a
selecting part for selecting at least one multimedia type of the
streaming communication contained within the starting
communication, referring the required bandwidth data recorded in
the priority data recording part and data representing bandwidth
required for relaying each streaming communication calculated by
the multimedia type data; an updating part for updating the data
which is recorded in the priority data recording part, newly adding
data representing a quantity of bandwidth for relaying the
streaming communication whose multimedia type is selected by the
selecting part and the communication identification data
representing a starting communication; a responding part for
transmitting data that represents the streaming communication to be
relayed by priority, selected by the selecting part, to the
communication control apparatus, as a response to the request
message. The selecting part selects the multimedia type of the each
streaming communication contained within the starting communication
not to exceed a predetermined upper limit of the total value of
bandwidth required for relaying the prioritized communication even
if adding the required bandwidth for relaying the starting
communication.
[0009] The call control apparatus transmits a request to prioritize
starting communication of a wireless terminal to a relay apparatus.
The request receiving part of the relay apparatus receives the
request message from the communication control apparatus together
with the communication identification data that represents
communication requested for priority and multimedia type data that
represents each multimedia type of streaming communication included
in the communication. The selecting part selects a multimedia type
of the streaming communication to be relayed prioritized. At this
time, the selecting part selects the multimedia type of streaming
communication so that the total value of required bandwidth does
not exceed a predetermined upper limit value for the required
bandwidth data which is recorded in the priority data recording
part even if adding requested bandwidth is consumed by the request
message. Therefore, the total bandwidth required by relaying the
streaming communications never exceed the upper limit for it. As
the result, the priority control part can relay, by priority, the
communication recorded in the priority data recording part stably.
Furthermore, the responding part can transmit a set of multimedia
types accepted by the call control apparatus. Consequently, the
communication control apparatus can control the starting of the
communication for each multimedia type of streams included in
communication of a wireless terminal, based on the multimedia type
of the stream to be relayed by priority in the relay apparatus.
Thus, the bandwidth control of communication to be relayed can be
performed considering the multimedia type of a stream included in
communication by a wireless terminal.
[0010] The relay apparatus according to the present invention may
further include a precedence recording part that records a
precedence of a plurality of multimedia types, wherein the
selecting part selects at least one multimedia type of the
streaming communication to be relayed by priority based on the
precedence recorded in the precedence recording part.
[0011] The selecting part selects a multimedia type of a stream to
be relayed by priority based on a precedence recorded in the
precedence recording part, so that the precedence of a stream to be
relayed can be managed by the precedence recording part.
[0012] In the relay apparatus according to the present invention,
it is preferable that the selecting part requests the communication
control apparatus to inquire of a wireless terminal that requests
starting of communication about a multimedia type of a streaming
communication to be relayed by priority, obtains data that
represents the multimedia type of the streaming communication to be
relayed by priority as a response to the request from the
communication control apparatus, and selects the multimedia type of
the streaming communication based on the obtained data.
[0013] The selecting part selects a multimedia type of a stream to
be relayed by priority based on data obtained as a response to a
request for an inquiry with respect to a wireless terminal.
Therefore, the multimedia type requested by a user of a wireless
terminal that is ready to start communication can be selected as
the multimedia type of a stream to be relayed by priority.
[0014] A relay apparatus according to the present invention for
relaying communication between a plurality of wireless terminals
and a wired network, includes: a wireless communication part for
enabling wireless communication between the plurality of wireless
terminals and the relay apparatus; a wired network connecting part
for connecting the relay apparatus and the wired network including
a communication control apparatus that controls start and ending of
communication of the wireless terminals; a plurality of priority
grade data recording parts for recording stream identification data
for identifying a streaming communication to be relayed by priority
with respect to each stage of priority provided in a plurality of
stages; a precedence recording part for recording precedence of a
plurality of multimedia types; a priority control part for relaying
a streaming communication specified by the stream identification
data recorded in the priority grade data recording part with higher
priority, by priority compared with a streaming communication
specified by the stream identification data recorded in the
priority grade data recording part with lower priority; a request
receiving part for receiving a request message containing the
communication identification data that represents a starting
communication of a wireless terminal ready to be started and
multimedia type data that represents each multimedia type of one or
a plurality of streaming communications included in the starting
communication; a priority determining part for determining priority
with respect to a streaming communication of each multimedia type
represented by the multimedia type data, based on the precedence
recorded in the precedence recording part; and an updating part for
recording the stream identification data for identifying the
streaming communication specified by the communication
identification data and the multimedia type data in the priority
grade data recording part in accordance with the priority
determined by the priority determining part, with respect to the
streaming communication of each multimedia type.
[0015] The priority determining part determines priority of a
stream of each multimedia type included in communication requested
for relay from the communication control apparatus, based on the
precedence recorded in the precedence recording part, and the
updating part records stream identification data for identifying a
stream specified by the communication identification data and the
multimedia type data in the priority grade data recording part in
accordance with the priority determined by the priority determining
part, with respect to a stream of each multimedia type. The
priority control part relays a stream specified by the stream
identification data recorded in the priority grade data recording
part with higher priority, by priority compared with a stream
specified by the stream identification data recorded in the
priority grade data recording part with lower priority. Thus, the
priority of relay is controlled for each multimedia type included
in communication, in accordance with the data in the priority grade
data recording part. Therefore, the relay apparatus can perform
bandwidth control of communication to be relayed, considering the
multimedia type of a stream included in the communication by a
wireless terminal.
[0016] A communication system according to the present invention
accessible wirelessly from a plurality of wireless terminals,
includes: a relay apparatus for relaying communication between a
wired network and the plurality of wireless terminals, and a
communication control apparatus connected to the relay apparatus
via the wired network. The communication control apparatus
includes: an interconnecting part for transmitting a request
message that contains communication identification data
representing a starting communication and multimedia type data
representing one or more multimedia types of the streaming
communication contained within the starting communication, based on
a request for starting of communication received from an arbitrary
wireless terminal; and a communication control part for receiving a
response to the request message transmitted by the interconnecting
part from the relay apparatus, and controlling the starting of
communication for each streaming communication included in the
starting communication based on the response. The relay apparatus
includes: a priority data recording part for recording
communication identification data that represents a prioritized
communication to be relayed by priority and the required bandwidth
data that represents a quantity of the transport bandwidth required
by the prioritized communication; a priority control part for
relaying the prioritized communication by priority compared with
the others based on the communication identification data recorded
in the priority data recording part; a request receiving part for
receiving, from the wireless terminal, a request message that
contains communication identification data representing a starting
communication and multimedia type data representing one or more
multimedia types of the streaming communication contained within
the starting communication; a selecting part for selecting at least
one multimedia type of the streaming communication contained within
the starting communication, referring the required bandwidth data
recorded in the priority data recording part and data representing
bandwidth required for relaying each streaming communication
calculated by the multimedia type data; an updating part for
updating the data which is recorded in the priority data recording
part, newly adding data representing a quantity of bandwidth for
relaying the streaming communication whose multimedia type is
selected by the selecting part and the communication identification
data representing a starting communication; a responding part for
transmitting data that represents the streaming communication to be
relayed by priority, selected by the selecting part, to the
communication control apparatus, as a response to the request
message. The selecting part selects the multimedia type of the each
streaming communication contained within the starting communication
not to exceed a predetermined upper limit of the total value of
bandwidth required for relaying the prioritized communication even
if adding the required bandwidth for relaying the starting
communication.
[0017] A relay method according to the present invention is a
method for a relay apparatus to relay communication between a
plurality of wireless terminals and a wired network. The relay
apparatus includes: a wireless communication part for enabling
wireless communication between the plurality of wireless terminals
and the relay apparatus; a wired network connecting part for
connecting the relay apparatus and the wired network including a
communication control apparatus that controls starting and ending
of communication between the wireless terminals; and a priority
data recording part for recording communication identification data
that represents a prioritized communication to be relayed by
priority and required bandwidth data that represents a quantity of
the transport bandwidth required by the prioritized communication.
The method includes: a request receiving operation of receiving,
from the wireless terminal, a request message that contains
communication identification data representing a starting
communication and multimedia type data representing one or more
multimedia types of the streaming communication contained within
the starting communication; a selecting operation of selecting at
least one multimedia type of the streaming communication contained
within the starting communication, by referring the required
bandwidth data recorded in the priority data recording part and
data representing bandwidth required for relaying each streaming
communication calculated by the multimedia type data; an updating
operation of updating the data which is recorded in the priority
data recording part, by newly adding data representing a quantity
of bandwidth for relaying the streaming communication whose
multimedia type is selected by the selecting operation and the
communication identification data representing a starting
communication; and a responding operation of transmitting data that
represents the streaming communication to be relayed by priority,
selected by the selecting operation, to the communication control
apparatus, as a response to the request message. In the selecting
operation, the multimedia type of the each streaming communication
contained within the starting communication is selected not to
exceed a predetermined upper limit of the total value of bandwidth
required for relaying the prioritized communication even if adding
the required bandwidth for relaying the starting communication.
[0018] A relay program according to the present invention is stored
in a recording medium and causes a computer to execute processing
of relaying communication between a plurality of wireless terminals
and a wired network. The computer includes: a wireless
communication part for enabling wireless communication between the
plurality of wireless terminals and the computer; a wired network
connecting part for connecting the computer and the wired network
including a communication control apparatus that controls starting
and ending of communication between the wireless terminals; and a
priority data recording part for recording communication
identification data that represents a prioritized communication to
be relayed by priority and required bandwidth data that represents
a quantity of the transport bandwidth required by the prioritized
communication. The program causes the computer to execute: request
receiving processing of receiving, from the wireless terminal, a
request message that contains communication identification data
representing a starting communication and multimedia type data
representing one or more multimedia types of the streaming
communication contained within the starting communication;
selecting processing of selecting at least one multimedia type of
the streaming communication contained within the starting
communication, by referring the required bandwidth data recorded in
the priority data recording part and data representing bandwidth
required for relaying each streaming communication calculated by
the multimedia type data; updating processing of updating the data
which is recorded in the priority data recording part, by newly
adding data representing a quantity of bandwidth for relaying the
streaming communication whose multimedia type is selected by the
selecting processing and the communication identification data
representing a starting communication; and responding processing of
transmitting data that represents the streaming communication to be
relayed by priority, selected by the selecting processing, to the
communication control apparatus, as a response to the request
message. In the selecting processing, the multimedia type of the
each streaming communication contained within the starting
communication is selected not to exceed a predetermined upper limit
of the total value of bandwidth required for relaying the
prioritized communication even if adding the required bandwidth for
relaying the starting communication.
[0019] A relay method according to the present invention is a
method for a relay apparatus to relay communication between a
plurality of wireless terminals and a wired network. The relay
apparatus includes: a wireless communication part for enabling
wireless communication between the plurality of wireless terminals
and the relay apparatus; a wired network connecting part for
connecting the relay apparatus and the wired network including a
communication control apparatus that controls starting and ending
of communication of the wireless terminals; a plurality of priority
grade data recording parts for recording stream identification data
for identifying a streaming communication to be relayed by priority
with respect to each stage of priority provided in a plurality of
stages; and a precedence recording part for recording precedence of
a plurality of multimedia types. The method includes: a priority
control operation of relaying a streaming communication specified
by the stream identification data recorded in the priority grade
data recording part with higher priority, by priority compared with
a streaming communication specified by the stream identification
data recorded in the priority grade data recording part with lower
priority; a request receiving operation of receiving a request
message containing the communication identification data that
represents a starting communication of a wireless terminal ready to
be started and multimedia type data that represents each multimedia
type of one or a plurality of streaming communications included in
the starting communication; a priority determining operation of
determining priority with respect to a streaming communication of
each multimedia type represented by the multimedia type data, based
on the precedence recorded in the precedence recording part; and an
updating operation of recording the stream identification data for
identifying the streaming communication specified by the
communication identification data and the multimedia type data in
the priority grade data recording part in accordance with the
priority determined by the priority determining operation, with
respect to the streaming communication of each multimedia type.
[0020] A relay program according to the present invention is stored
in a recording medium and causes a computer to execute processing
of relaying communication between a plurality of wireless terminals
and a wired network. The computer including: a wireless
communication part for enabling wireless communication between the
plurality of wireless terminals and the computer; a wired network
connecting part for connecting the computer and the wired network
including a communication control apparatus that controls starting
and ending of communication of the wireless terminals; a plurality
of priority grade data recording parts for recording stream
identification data for identifying a streaming communication to be
relayed by priority with respect to each stage of priority provided
in a plurality of stages; and a precedence recording part for
recording precedence of a plurality of multimedia types. The
program causes the computer to execute: priority control processing
of relaying a stream specified by the stream identification data
recorded in the priority grade data recording part with higher
priority, by priority compared with a stream specified by the
stream identification data recorded in the priority grade data
recording part with lower priority; request receiving processing of
receiving a request message containing the communication
identification data that represents a starting communication of a
wireless terminal ready to be started and multimedia type data that
represents each multimedia type of one or a plurality of streaming
communications included in the starting communication; priority
determining processing of determining priority with respect to a
streaming communication of each multimedia type represented by the
multimedia type data, based on the precedence recorded in the
precedence recording part; and updating processing of recording the
stream identification data for identifying the streaming
communication specified by the communication identification data
and the multimedia type data in the priority grade data recording
part in accordance with the priority determined in the priority
determining processing, with respect to the streaming communication
of each multimedia type.
[0021] According to the present invention, a relay apparatus, a
relay method, a relay program, and a communication system can be
provided, which are capable of controlling the bandwidth of
communication to be relayed, considering the multimedia type
included in communication by a wireless terminal.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a diagram showing an entire configuration of a
wireless communication system in Embodiment 1.
[0023] FIG. 2 is a functional block diagram showing a detailed
configuration of an AP 1a.
[0024] FIG. 3 is a diagram showing a specific example of data
recorded in a priority data recording part 13.
[0025] FIG. 4 is a diagram showing a specific example of data
recorded in a precedence recording part 11.
[0026] FIG. 5 is a diagram showing an operation example of the
wireless communication system in the case where communication is
performed by wireless terminals.
[0027] FIG. 6 is a sequence diagram showing an example of
processing when a request for a bandwidth reservation is
transmitted to the AP 1a.
[0028] FIGS. 7A and 7B show specific examples of a part of SDP
data.
[0029] FIG. 8 is a diagram showing an example of a required
bandwidth table 35 for recording a required bandwidth with respect
to each multimedia type.
[0030] FIG. 9 is a sequence diagram showing an example of
processing when a request for a bandwidth reservation is
transmitted to the AP 1a.
[0031] FIG. 10 is a diagram showing an example of data recorded in
a precedence recording part 11 in a first modified example.
[0032] FIG. 11 is a diagram showing an example of data recorded in
the precedence recording part 11 in a second modified example.
[0033] FIG. 12 is a diagram showing a required available bandwidth
table 41.
[0034] FIG. 13 is a functional block diagram showing a detailed
configuration of an AP 10a according to Embodiment 2.
[0035] FIG. 14 is a diagram showing a specific example of data
recorded in a priority grade data recording part 16.
[0036] FIG. 15 is a sequence diagram showing an example of
processing when a request for a bandwidth reservation is
transmitted to an AP.
[0037] FIG. 16 is a functional block diagram showing a detailed
configuration of an AP 100a according to Embodiment 3.
[0038] FIG. 17 is a sequence diagram showing an example of
processing when a request for a bandwidth reservation is
transmitted to the AP 100a.
DETAILED DESCRIPTION OF THE INVENTION
[0039] Hereinafter, the present invention will be described in
detail by way of one embodiment with reference to the drawings.
Embodiment 1
[0040] FIG. 1 is a diagram showing an entire configuration of a
wireless communication system in Embodiment 1. The wireless
communication system in the present embodiment includes an SIP
server 2, wireless LAN access points (hereinafter, referred to as
APs) 1a, 1b, a wired terminal 4, and wireless terminals 3a-3d. The
SIP server 2, the APs 1a, 1b, and the wired terminal 4 are
connected to each other through a wire by a wired local area
network (LAN) 6. The wireless terminals 3a-3d can access the AP 1a
or AP 1b wirelessly. FIG. 1 shows, as an example, a state in which
the wireless terminals 3a, 3b can access the AP 1a, and the
wireless terminals 3c, 3d can access the AP 1b. In this state, the
AP 1a relays the communication between the wireless terminals 3a,
3b and the wired LAN 6, and the AP 1b relays the communication
between the wireless terminals 3c, 3d and the wired LAN 6.
[0041] Each of the wireless terminals 3a to 3d communicates with
another wireless terminal or the wired terminal 4 via the AP 1a or
1b, and the wired LAN 6. The starting of communication performed by
the wireless terminal is controlled by the SIP server 2.
[0042] The communication of the wireless terminal controlled by the
SIP server 2 is specified by a transmission origin and a
transmission destination. One or a plurality of transmission
destinations may be used. The communication controlled by the SIP
server 2 includes one or a plurality of streams. The stream is the
communication channel to send streaming data in real time. Examples
of the stream include audio data to be transmitted in a telephone
conversation, and video data distributed in a moving picture
distribution. Therefore, the communication controlled by the SIP
server 2 has an attribute such as the number of streams.
Furthermore, each stream has an attribute such as a multimedia
type. Examples of the multimedia type of a stream include an audio,
a character, a moving picture, a still picture, and pointing
position information. Furthermore, two multimedia types may be
included in an audio, for example, as in a right audio and a left
audio of a stereo audio. In communication, different streams for
each multimedia type are transmitted. In the present embodiment, as
an example, the case will be described where the wireless terminals
3a-3d are IP telephones with a video reproducing function, and
communication including multimedia types of a video stream and an
audio stream can be performed.
[0043] The wireless terminals 3a-3d are not limited to IP
telephones. Examples of the wireless terminals 3a-3d include a
video reproducing terminal, a PDA, an electronic organizer, a game
machine, and a GPS terminal. Furthermore, the communication of the
wireless terminal whose starting is controlled by the SIP server 2
is not limited to a telephone conversation. Examples of the
communication of the wireless terminal include a video
distribution, a music distribution, an on-line game, a stock price
information distribution, a remote presentation, a TV conference,
and a monitoring camera image transmission. Furthermore, the number
of the wireless terminals, and the number of the APs and the wired
terminals connected to the wired LAN 6 are not limited to those
shown in FIG. 1.
[0044] The SIP server 2 includes a wired LAN interface 25, an
interconnecting part 21, a communication control part 22, and a
terminal information recording part 23. The wired LAN interface 25
mediates the exchange of data between the SIP server 2 and the
wired LAN 6 in conformity with the specification of the wired
LAN.
[0045] The communication control part 22 receives a request for the
starting and ending of communication from any of the wireless
terminals 3a-3d, and controlling the starting and ending of
communication by the wireless terminal. The communication control
part 22 transmits various messages to the wireless terminal,
thereby controlling the starting and ending of communication.
[0046] In the terminal information recording part 23, communication
identification data for identifying the communication controlled by
the communication control part 22 is recorded. The communication
identification data contains, for example, information representing
the position on a LAN of a communication terminal (including a
wireless terminal and a wired terminal) that performs
communication, and information for identifying a communication
terminal. In the present embodiment, an example will be described
in which the communication control part 22 controls the starting
and ending of communication in accordance with a session initiation
protocol (SIP).
[0047] The interconnecting part 21 requests the allocation of a
bandwidth of communication ready to be started by the communication
control part 22, and the deallocation of a bandwidth of ended
communication. The interconnecting part 21 requests the allocation
of a bandwidth, thereby requesting the APs 1a, 1b to relay, by
priority, the communication ready to be started.
[0048] The SIP server 2 is composed of one or a plurality of
computers such as a server machine, a personal computer, and a work
station. Each function of the wired LAN interface 25, the
interconnecting part 21, and the communication control part 22 is
realized when a CPU of a computer executes a predetermined program.
Furthermore, the terminal information recording part 23 is embodied
by a recording medium contained in a computer or an external
recording apparatus accessible by the computer. The SIP server 2
may be configured on one computer, or may be distributed in a
plurality of computers connected to the wired LAN 6.
[0049] FIG. 2 is a functional block diagram showing a detailed
configuration of the AP 1a. The configuration of the AP 1b is also
the same as that of the AP 1a shown in FIG. 2. The AP 1a includes a
wired LAN interface 5, a request receiving part 7, an updating part
8, a selecting part 9, a precedence recording part 11, a priority
data recording part 13, a responding part 14, a priority control
part 15, and a wireless LAN interface 17.
[0050] The wired LAN interface 5 mediates the exchange of data
between the AP 1a and the wired LAN 6 in conformity with the
specification of a wired LAN. The wireless LAN interface 17
mediates the wireless exchange of data with respect to the wireless
terminals 3a and 3b in conformity of the specification of the
wireless LAN. The communication between the wireless terminals 3a,
3b and the wired LAN 6 is relayed by the wireless LAN interface 17
and the wired LAN interface 5.
[0051] The priority control part 15 controls the priority of
communication relayed by the wireless LAN interface 5, based on
data recorded in the priority data recording part 13. The priority
data recording part 13 stores communication identification data
representing communication to be relayed by priority, and required
bandwidth data representing a bandwidth required for communication
to be relayed by priority.
[0052] FIG. 3 is a diagram showing a specific example of data
recorded in the priority data recording part 13. FIG. 3 shows an
example in which data to be recorded in the priority data recording
part 13 is recorded as a priority table 31. The priority table 31
stores data representing a source IP address, a destination IP
address, a call state, and a required bandwidth so that they are
associated for each communication to be relayed by priority. A
source IP address and a destination IP address are examples of
communication identification data representing communication to be
relayed by priority. The call state is data representing the state
of communication represented by communication identification data.
The required bandwidth is data representing a bandwidth required
for communication represented by the communication identification
data.
[0053] The communication identification data may be data capable of
identifying communication, and is not limited to an example shown
in FIG. 3. For example, as the communication identification data
may contain a port number in addition to an IP address.
[0054] The priority control part 15 controls the wireless LAN
interface 17 so that communication represented by the communication
identification data recorded in the priority data recording part 13
is relayed by priority compared with the other communications.
[0055] The request receiving part 7 receives a request for
relaying, by priority, communication of the wireless terminal ready
to be started, from the interconnecting part 21 of the SIP server
2. At this time, the request receiving part 7 receives the
communication identification data representing communication to be
relayed by priority, and a set of multimedia type data representing
the multimedia type of one or a plurality of streams included in
the communication. The streams included in the communication are
transmitted as separated streams for each multimedia type. Thus,
the streams included in the communication can also be identified
based on the multimedia type data.
[0056] The updating part 8 requests the selecting part 9 to select
a stream to be relayed by priority among a plurality of streams
capable of being identified based on the multimedia type data. The
selecting part 9 calculates requiring bandwidth for relaying a
stream of each multimedia type represented by the multimedia type
data. The data representing a bandwidth required for relaying a
stream of each multimedia type can be calculated, for example,
using a fixed value for each multimedia type. Furthermore, a
required bandwidth may be calculated on demand in accordance with a
multimedia type. Furthermore, the data representing a required
bandwidth may be contained in the multimedia type data received by
the request receiving part 7.
[0057] The selecting part 9 selects a set of multimedia types of
streaming communications to be relayed by priority, using the
determined data of requiring bandwidth and the required bandwidth
data recorded in the priority data recording part 13. The selecting
part 9 selects a set of multimedia types so that, in the case of
additionally recording the data representing a bandwidth required
for relaying streams of the selected multimedia type, the sum of
bandwidths represented by the required bandwidth data does not
exceed a predetermined upper limit value. Furthermore, the
selecting part 9 selects a multimedia type in accordance with a
precedence recorded in the precedence recording part 11.
[0058] The precedence recording part 11 records the order of the
priority for multimedia types. FIG. 4 shows a specific example of
data recorded in the precedence recording part 11. In the example
shown in FIG. 4, a precedence and a multimedia type are recorded in
a multimedia priority table 32 so as to be associated with each
other. Thus, by recording a precedence for each multimedia type in
the APs, each AP can control a precedence for each multimedia type
of a stream to be relayed in accordance with the situation peculiar
to the AP.
[0059] The updating part 8 additionally records the data
representing a bandwidth required for relaying the stream selected
by the selecting part 9 and the communication identification data
received by the request receiving part 7 in the priority data
recording part 13. Furthermore, the responding part 14 transmits
the stream of the multimedia type selected by the selecting part 9
(i.e., the data representing a stream to be relayed by priority) to
the SIP server 2 as a response to the request. This response is
transmitted to the SIP server 2 via the wired LAN interface 5.
[0060] The APs 1a, 1b are composed of a wireless communication
relay apparatus with a computer incorporated therein. Each function
of the wired LAN interface 5, the request receiving part 7, the
updating part 8, the selecting part 9, the responding part 14, the
priority control part 15, and the wireless LAN interface 17 is
realized when a processor provided in a computer executes a
predetermined program. Furthermore, the priority data recording
part 13 and the precedence recording part 11 are embodied by a
recording medium contained in a computer or an external recording
apparatus accessible by the computer.
(Operation Example of the Wireless Communication System)
[0061] Next, an operation example of a wireless communication
system in the case where communication is performed by wireless
terminals will be described. FIG. 5 shows an operation example of a
wireless communication system in the case where communication by
the wireless terminals shown in FIG. 1 is performed. FIG. 5 shows,
as an example, the processing in which the wireless terminals 3a,
3b accessible to the AP 1a start and end communication.
[0062] When the wireless terminal 3a is started up in a
communication area of the AP 1a, the wireless terminal 3a sends a
search message for searching for an AP (#1). The AP 1a responds to
the search message, whereby the wireless terminal 3a recognizes the
AP 1a as an accessible AP.
[0063] After that, the wireless terminal 3a transmits a REGISTER
message to the SIP server 2 (#2). The REGISTER message contains,
for example, terminal information such as positional information
(e.g., an IP address, a port number, etc.) of the wireless terminal
3a and an identifier (e.g., a telephone number, a user ID, an SIP
address, etc.) for calling the wireless terminal 3a. The SIP server
2 records the terminal information contained in the REGISTER
message in the terminal information recording part 23. When the SIP
server succeeds in this recording, the SIP server 2 transmits an OK
message to the wireless terminal 3a (#3).
[0064] Similarly, when the wireless terminal 3b transmits a search
message to the AP 1a (#4), and receives a response, the wireless
terminal 3b transmits a REGISTER message to the SIP server 2 (#5).
The SIP server 2 records the terminal information of the wireless
terminal 3b, and transmits an OK message to the wireless terminal
3b (#6). The REGISTER message and the OK message are those which
are defined by an SIP. Furthermore, INVITE, TRYING, RINGING, ACK,
and BYE messages described below are also those which are defined
by the SIP.
[0065] The wireless terminal 3a transmits an INVITE message for the
wireless terminal 3b to the SIP server 2 (#7). Consequently, the
wireless terminal 3a requests the SIP server 2 to start
communication with the wireless terminal 3b. The INVITE message
contains a multimedia type data representing a set of multimedia
types of streams included in communication ready to be started, in
addition to communication identification data representing
communication ready to be started. The multimedia type data is
contained, for example, in the INVITE message in a form according
to a Session Description Protocol (SDP). Hereinafter, data in a
form according to an SDP contained in the INVITE message is
referred to as SDP data. The multimedia type data is contained in
the SDP data. The SDP data may contain, for example, a protocol
used in the transmission of a stream, information (e.g., codec
information, etc.) to be a base for a bandwidth required for
relaying a stream, and the like, in addition to a multimedia
type.
[0066] The SIP server 2 having received the INVITE message
specifies the positions of the wireless terminals 3a, 3b with
reference to the terminal information recording part 23.
Consequently, the SIP server 2 specifies that the AP that relays
the communication ready to be started is the AP 1a. The SIP server
2 requests the AP 1a to make a bandwidth reservation for
communication ready to be started (#8). More specifically, the SIP
server 2 requests the AP 1a to relay, by priority, the
communication ready to be started. At this time, the SIP server 2
transmits communication identification data for the communication
ready to be started, and SDP data contained in the INVITE message
to the AP 1a.
[0067] The AP 1a having received the request for a bandwidth
reservation records the communication identification data, the
required bandwidth data representing a bandwidth required for
communication, and the data representing that bandwidth allocation
is being reserved in the priority data recording part 13.
Consequently, a bandwidth allocation is reserved. At a time of
reservation, the AP 1a selects a set of multimedia type of a stream
accepted as being relayed by priority, among the streams included
in the communication. The bandwidth required for relaying the
stream of the selected multimedia type is recorded in the priority
data recording part 13 as required bandwidth data. When the AP 1a
reserves a bandwidth, the AP 1a transmits an OK message to the SIP
server 2 as a response with respect to the request for a bandwidth
reservation (#9). The detail of processing in which the AP 1a
reserves bandwidth allocation will be described later. At this
time, the OK message contains SDP data. The SDP data contains
information representing the set of streams whose bandwidth
allocation was successfully reserved.
[0068] When the SIP server 2 receives the OK message, the SIP
server 2 transmits an INVITE message to the wireless terminal 3b
(#10). Furthermore, the SIP server 2 transmits a TRYING message to
the wireless terminal 3a (#11). In the case where the AP 1a fails
in reserving bandwidth allocation, and the SIP server 2 receives an
error message, the SIP server 2 may, for example, transmit a
disconnection message to the wireless terminal 3a without starting
the communication between the wireless terminals 3a, 3b.
[0069] The wireless terminal 3b having received the INVITE message
from the SIP server 2 transmits a RINGING message representing
"during calling" to the SIP server 2 (#12). The RINGING message
received by the SIP server 2 is transmitted to the wireless
terminal 3a (#13).
[0070] When a user of the wireless terminal 3b performs an
operation of accepting a request for the starting of communication
with respect to the wireless terminal 3b, an OK message is
transmitted from the wireless terminal 3b to the SIP server 2
(#14). The SIP server 2 requests the AP 1a to allocate a bandwidth
for communication ready to be started (#15). Because of this, the
AP 1a finalizes the allocation of a bandwidth reserved in #8.
Consequently, the wireless communication between the AP 1a and the
wireless terminal 3a, and the wireless communication between the AP
1 bandwidth the wireless terminal 3b are performed by priority
compared with the other wireless communications. The specific
processing of finalizing bandwidth allocation of communication will
be described later.
[0071] The SIP server 2 transmits an OK message to the wireless
terminal 3a (#16). At this time, the OK message contains SDP data.
The SDP data contains information representing a set of multimedia
type of the streams whose bandwidth was able to be allocated in the
AP 1a. Thus, the wireless terminal 3a can start communication with
respect to the stream whose bandwidth was able to be allocated.
[0072] The wireless terminal 3a having received the OK message
transmits an ACK message to the wireless terminal 3b via the SIP
server 2 (#17, #18). Because of this, communication is started
between the wireless terminals 3a, 3b. This communication is
performed in accordance with, for example, RTP/AVP (Real-time
Transport Protocol using Audio Video Profile).
[0073] In this communication, the stream whose bandwidth was able
to be allocated in the AP 1a is exchanged between the wireless
terminals 3a, 3b. For example, in the case where the multimedia
type data contained a stream whose multimedia type is an audio and
a stream whose multimedia type is a video are allocated in the AP
1a, an audio stream and a video stream are exchanged between the
wireless terminals 3a, 3b. Since streams are transmitted as
packets, the AP 1a determines whether or not streams are relayed by
priority for each packet to be relayed.
[0074] In the case where a user of one of the wireless terminals
3a, 3b requests the ending of the communication, a BYE message
requesting the ending of the communication is transmitted from that
wireless terminal to the SIP server 2. In the example shown in FIG.
5, the wireless terminal 3a transmits a BYE message (#19). The SIP
server 2 having received the BYE message transmits the BYE message
to the wireless terminal 3b (#20). The wireless terminal 3b having
received the BYE message transmits an OK message representing that
the ending of the communication is accepted to the SIP server 2
(#201).
[0075] The SIP server 2 having received the OK message requests the
AP 1a to deallocate the bandwidth allocated for communication
(#202). The AP 1a deallocates the allocated bandwidth by deleting
communication identification data and required bandwidth data of
the corresponding communication from the priority data recording
part 13. The SIP server 2 further transmits the OK message to the
wireless terminal 3a (#203). Consequently, the communication
between the wireless terminals 3a and 3b is ended.
[0076] The example shown in FIG. 5 corresponds to the processing in
the case where both the wireless terminals 3a, 3b can access the AP
1a. In the case where the wireless terminals 3a, 3b respectively
access the APs (e.g., the AP 1a and AP 1b), the processings of the
AP 1a and the SIP server 2 shown in FIG. 5 (#8, #9, #15, #202) are
performed with respect to the respective APs 1a, 1b. At this time,
the SIP server 2 can request the respective APs 1a, 1b to allocate
bandwidths so that the bandwidth allocated in the AP 1a becomes the
same as the bandwidth allocated in the AP 1b.
(Processing of Bandwidth Reservation)
[0077] FIG. 6 is a sequence diagram showing an example of
processing when the request for a bandwidth reservation is
transmitted from the SIP server 2 to the AP 1a in #8 shown in FIG.
5. More specifically, the processing shown in FIG. 6 is exemplary
processing in the case where the SIP server 2 having received an
INVITE message requesting the starting of communication from the
wireless terminal 3a requests the AP 1a to reserve bandwidth
allocation for the communication. In FIG. 6, first, the
interconnecting part 21 of the SIP server 2 requests the request
receiving part 7 of the AP 1a to reserve a bandwidth of
communication ready to be started (#8). At this time, the
interconnecting part 21 transmits SDP data contained in the INVITE
message received from the wireless terminal 3a to the AP 1a.
[0078] The request receiving part 7 decodes the received SDP data,
and reads communication identification data for identifying the
communication ready to be started. The communication identification
data is, for example, an IP address of the wireless terminal 3a and
an IP address of the wireless terminal 3b.
[0079] Furthermore, the request receiving part 7 decodes the
received SDP data (#801), and generates data representing the
number of streams included in the communication, multimedia types,
and a required bandwidth of a stream for each multimedia type.
FIGS. 7A and 7B show specific examples of a part of the SDP data.
FIG. 7A represents an example of a portion of data representing a
stream included in the communication ready to be started, among the
SDP data received by the request receiving part 7.
[0080] In the SDP data shown in FIG. 7A, each stream included in
the communication is represented by a character string representing
a stream. Each stream is identified by a stream ID. For example,
"m=audio" in the first line represents that the multimedia type is
an audio. "49170" represents a port number for
transmitting/receiving the stream, and is used as an stream ID for
identifying the stream, in combination with a transmission
origin/reception destination address. "RTP/AVP" represents a
communication protocol of the stream, and "0" represents a
compression form (codec) of the stream, respectively. The request
receiving part 7 can generate data representing that the number of
streams included in the communication is 2, and the multimedia
types of the streams included in the communication are an audio and
a video, from the data shown in FIG. 7A.
[0081] Furthermore, the request receiving part 7 determines each
required bandwidth for the stream whose multimedia type is an audio
and the stream whose multimedia type is a video. The required
bandwidth can be determined, for example, using a required
bandwidth previously recorded with respect to each multimedia type.
FIG. 8 shows an example of a required bandwidth table 35 for
recording a required bandwidth with respect to each multimedia
type. For example, the required bandwidth table 35 as shown in FIG.
8 is previously recorded in the AP 1a. The request receiving part 7
can determine that a bandwidth required for relaying the stream
whose multimedia type is an audio is 128 and a bandwidth required
for relaying the stream whose multimedia type is a video is 420, by
referring to the required bandwidth table 35.
[0082] In the present embodiment, as an example, the required
bandwidth of particular communication in the AP is a value
representing to which degree a communication amount by the
particular communication occupies among the maximum communication
amount per unit time capable of being relayed by the AP. As an
example of this value, in the case where the communication amount
per unit time of an audio stream is 128 kbps when the link speed
between the AP and a certain terminal (A communication mode
determined between the terminal and the AP. For example, in IEEE
802.11b, there are 1 Mbps, 2 Mbps, 5.5 Mbps, and 11 Mbps
communication modes, and each of them represents a logically
maximum communication amount) is 11 Mbps, the required bandwidth of
128 kbps is determined. This means that 128 k/11 M among the
logically maximum communication amount capable of being relayed by
the AP is used for relaying an audio stream. In this case, when the
link speed between the AP and the terminal changes, the value of
the required bandwidth is converted to a value at 11 Mbps in
accordance with the link speed. For example, in the case where the
required bandwidth of an audio stream is 128 kbps at the link speed
of the AP of 11 Mbps, when the link speed between the AP and the
terminal changes to 5.5 Mbps, the maximum communication amount per
unit time capable of being performed by the AP and the terminal
becomes a half that at a time of the link speed of 11 Mbps.
Therefore, the required bandwidth at a time of the link speed of
5.5 Mbps is converted to 256 kbps that is a double of the required
bandwidth at a time of the link speed of 11 Mbps.
[0083] Even at the link speed of 11 Mbps, because of the influence
of the physical performance of a relay apparatus, an access system,
and the like, the maximum throughput that can be used actually
varies depending upon the type of a relay apparatus. Thus, the
upper limit value of a bandwidth allocated to the communication to
be relayed by priority is calculated based on the value
representing the performance of the type of the relay apparatus.
For example, in the case of the type capable of generating an
effective throughput of 5 Mbps, 5 Mbps can be set to the upper
limit value of a bandwidth allocated to the communication to be
relayed by priority.
[0084] The method for representing a required bandwidth is not
limited to the above method. For example, the ratio at which a
frequency bandwidth to be used for the particular communication
occupies among the frequency bandwidths that can be used for the
communication between the AP and the terminal may be represented as
a required bandwidth for the communication.
[0085] The request receiving part 7 gives data representing the
number of streams included in the communication, the multimedia
types of the streams included in the communication, and the
required bandwidth of each multimedia type, generated from the SDP
data as described above, to the updating part 8 (#802). The
updating part 8 obtains a bandwidth that is being used by the
communication relayed by priority or a bandwidth to be used, with
reference to the priority data recording part 13 (#803a, #803b).
The bandwidth is represented by, for example, a sum of bandwidths
represented by required bandwidth data recorded in the priority
data recording part 13. For example, the sum of bandwidths
represented by the required bandwidth data recorded in the priority
table 31 shown in FIG. 3 becomes 128+420+128=676.
[0086] When the updating part 8 obtains the bandwidth in use, the
updating part 8 calculates a usable bandwidth, using the obtained
the bandwidth in use. The usable bandwidth is obtained, for
example, by calculating the difference between the bandwidth in use
and a predetermined upper limit value. For example, in the case
where the obtained bandwidth in use is the above-mentioned 676, and
the predetermined upper limit value is 1000, the usable bandwidth
becomes 1000-676=324.
[0087] The predetermined upper limit value used for calculating the
usable bandwidth may be, for example, the maximum value of a
bandwidth that can be used for wireless communication by the AP 1a,
or may be a value obtained by subtracting a predetermined required
available bandwidth from the maximum value. Furthermore, the
updating part 8 may update a required available bandwidth depending
upon the situation. An example in which a required available
bandwidth is changed depending upon a common use will be described
later.
[0088] The updating part 8 having obtained the usable bandwidth
compares a required bandwidth for each multimedia type of a stream
included in the communication with the usable bandwidth. The
updating part 8 determines whether or not the required bandwidth
required for relaying all the streams included in the communication
exceeds the usable bandwidth. For example, in the case where the
communication includes a stream whose multimedia type is an audio
and a stream whose multimedia type is a video, the bandwidth
required for the communication of an audio stream and a video
stream becomes 128+420=548 in the above example. On the other hand,
since the usable bandwidth is 324 in the above example, it is
determined that the required bandwidth exceeds the usable bandwidth
in this case.
[0089] If the required bandwidth exceeds the usable bandwidth, the
selecting part 9 is requested to select the multimedia type of a
stream to be relayed by priority (#804a). If the required bandwidth
does not exceed the usable bandwidth, a bandwidth is reserved
(#807a) without requesting selection (without performing the
processings in #804a to 806).
[0090] The selecting part 9 having received a request for selection
obtains a precedence of the multimedia type (#805b), with reference
to the precedence recording part 11 (#805a). The selecting part 9
selects a multimedia type in a range where the required bandwidth
does not exceed the usable bandwidth, in the order from the
obtained multimedia type having the highest precedence (#806). For
example, in the case where the data recorded in the precedence
recording part 11 is the multimedia priority table 32 shown in FIG.
4, and the multimedia types of streams included in the
communication are an audio and a video, the selecting part 9
determines whether or not the required bandwidth of an audio having
a high priority exceeds the usable bandwidth. In this case, the
required bandwidth (128 in the present example) of an audio does
not exceed the usable bandwidth (324 in the present example), so
that the selecting part 9 selects an audio. Similarly,
determination is also made with respect to a video. The required
bandwidth (420 in the present example) of a video exceeds a
bandwidth (324-128=196 in the present example) excluding the
required bandwidth of an audio from the usable bandwidth, so that a
video is not selected.
[0091] The selecting part 9 notifies the updating part 8 of a
selection result (#804b). Herein, the selecting part 9 notifies the
updating part 8 that the selecting part 9 has selected only an
audio among multimedia types i.e., an audio and a video) of streams
included in the communication. The updating part 8 records data
that represents a required bandwidth of a stream of the multimedia
type selected by the selecting part 9, and the communication
identification data in the priority data recording part 13. In the
present example, the required bandwidth (128) of an audio stream
and the communication identification data (an IP address of the
wireless terminal 3a and an IP address of the wireless terminal 3b)
are recorded in the priority data recording part 13. Furthermore,
as data representing the state of the priority data recording part
13, data representing "reservation" is recorded. Consequently,
bandwidth allocation for relaying only communication of an audio by
priority is reserved. When the updating part 8 is notified of the
completion of data recording (#807b), the updating part 8 notifies
the responding part 14 of the multimedia type reserved for the
bandwidth allocation. More specifically, the responding part 14 is
notified of the multimedia type (an audio in the present example)
selected by the selecting part 9 (#808).
[0092] The responding part 14 corrects the SDP data received by the
request receiving part 7 so that the multimedia type of the stream
reserved for bandwidth allocation is represented as the SDP data.
For example, the responding part 14 leaves only information
representing the stream reserved for bandwidth allocation, among
information representing the streams of the SDP data, and deletes
information representing the other streams. FIG. 7B shows a state
in which the SDP data shown in FIG. 7A is corrected, and only the
information representing the stream reserved for bandwidth
allocation is left. Information representing a stream whose
multimedia type is an audio "m=audio" is left, and information
representing a stream whose multimedia type is a video "m=video" is
deleted. In the case where the selecting part 9 does not select a
multimedia type, the SDP data is not corrected.
[0093] The responding part 14 transmits the SDP data thus corrected
to the interconnecting part 21 of the SIP server 2 together with an
OK message. The interconnecting part 21 receives the OK message and
the SDP data, as a response to the request for a bandwidth
reservation (#9). Because of this, the SIP server 2 can obtain data
representing that a bandwidth can be allocated by the AP 1a only
with respect to the communication of a stream whose multimedia type
is an audio.
[0094] The processing shown in FIG. 6 is an example, and the
reservation processing of bandwidth allocation by the AP is not
limited to the example shown in FIG. 6.
(Processing of Bandwidth Allocation)
[0095] FIG. 9 is a sequence diagram showing an example of
processing when a request for bandwidth allocation is transmitted
from the IP server 2 to the AP 1a in #15 shown in FIG. 5. The
processing shown in FIG. 9 is an example of processing after the
processing of reserving bandwidth allocation shown in FIG. 6 is
performed by the AP 1a. More specifically, the processing shown in
FIG. 9 is an example of processing in the case where the SIP server
2 having received an OK message of accepting the starting of
communication from the wireless terminal 3b requests the AP 1a to
allocate a bandwidth that has already been reserved for the
communication. In FIG. 9, first, the interconnecting part 21 of the
SIP server 2 requests the request receiving part 7 of the AP 1a to
allocate a bandwidth of the communication ready to be started
(#15). At this time, the interconnecting part 21 transmits
communication identification data of the communication ready to be
started and SDP data contained in the OK message received from the
wireless terminal 3b to the AP 1a. The request receiving part 7
decodes the received SDP data to read the communication
identification data for identifying the communication ready to be
started (#1501). The communication identification data is, for
example, an IP address of the wireless terminal 3a and an IP
address of the wireless terminal 3b. The request receiving part 7
gives the read IP addresses to the updating part 8 (#1502). The
updating part 8 updates the state of the communication represented
by the IP addresses given from the request receiving part 7 from
"reservation" to "under communication", among the data recorded in
the priority data recording part 13. Consequently, the allocation
of a bandwidth is completed (#1503a).
[0096] When the updating part 8 receives the notification of the
completion of update from the priority data recording part 13
(#1503b), the updating part 8 gives an OK message, stating that a
bandwidth has been allocated, to the responding part 14 (#1504),
and the responding part 14 transmits a response, stating that a
bandwidth has been allocated, to the interconnecting part 21 of the
SIP server 2 (#1505).
[0097] Owing to the above processings, a bandwidth is allocated.
The priority control part 15 of the AP 1a relays, by priority, the
communication whose state is under communication, with reference to
the priority data recording part 13. Thus, when the communication
of an audio stream is started between the wireless terminal 3a and
the wireless terminal 3b, the communication is relayed by priority,
compared with the other communications recorded in the priority
data recording part 13 in the AP 1a.
(First Modified Example of Multimedia Type Selection
Processing)
[0098] Hereinafter, a modified example of the processing will be
described in which the selecting part 9 selects a multimedia type
in #806 of the processing shown in FIG. 6. FIG. 10 shows an example
of data to be recorded in the precedence recording part 11 to which
the selecting part 9 refers in the first modified example. As shown
in FIG. 10, in the precedence recording part 11 in the modified
example, a multimedia type combination table 36, a multimedia
priority table A, a multimedia priority table B, and a multimedia
priority table C are recorded. The multimedia type combination
table 36 stores the data representing combination patterns of
multimedia types of streams included in the communication, and the
data representing multimedia priority tables to be referred to so
that they are associated with each other for each combination of
the multimedia types.
[0099] The selecting part 9 obtains data representing a multimedia
priority table corresponding to a combination of multimedia types
of streams included in the communication ready to be started, with
reference to the multimedia type combination table 36. For example,
in the case where multimedia types of streams included in the
communication ready to be started are an audio and a character, the
selecting part 9 obtains data representing the corresponding
multimedia priority table A with reference to the multimedia type
combination table 36. The selecting part 9 selects an audio or a
character, with reference to the priority of multimedia types in
the multimedia priority table A.
[0100] Thus, by providing a multimedia priority table for each
combination of multimedia types of streams included in the
communication, the priority of multimedia types can be changed
depending upon the combination of multimedia types of streams
included in the communication ready to be started. For example, in
the case of the communication including streams of a right audio
and a left audio of a stereo audio, and a video stream, as shown in
the multimedia priority table C, a right audio, a video, and a left
audio can be relayed by priority in this order. Furthermore, as
another example, in the case of communicating pointing position
information of a pen tablet and presentation information containing
an audio and a video by streaming, an audio, pointing information,
and a video can be relayed by priority in this order. In the case
of the presentation, a video is a still picture in most cases, so
that a problem is unlikely to occur even if a delay occurs in the
communication of a video, and a priority may be decreased.
(Second Modified Example of Multimedia Type Selection
Processing)
[0101] Herein, another modified example of the processing in which
the selecting part 9 selects a multimedia type will be described.
FIG. 11 shows an example of data to be recorded in the precedence
recording part 11 to which the selecting part 9 refers in the
second modified example. As shown in FIG. 11, the precedence
recording part 11 in the present modified example stores a terminal
type table 37, a multimedia priority table for a telephone 38a, a
multimedia priority table for a camera 38b, and a multimedia
priority table for a TV conference system 38c. The terminal type
table 37 stores information regarding a terminal that is ready to
communicate, and data representing a multimedia priority table to
be referred to so that they are associated with each other.
[0102] The selecting part 9 obtains information regarding a
wireless terminal that is ready to communicate from the SDP data
received by the request receiving part 7. Examples of the
information regarding the terminals include data representing a
product name or a specification name. The selecting part 9 obtains
data representing a multimedia priority table corresponding to a
terminal that performs communication ready to be started, with
reference to the terminal type table 37. For example, in the case
where a terminal that performs communication ready to be started is
a telephone, the selecting part 9 obtains data representing the
corresponding multimedia priority table for a telephone 38a with
reference to the terminal type table 37. The selecting part 9
selects a set of multimedia types with reference to the priority of
multimedia types of the multimedia priority table for a telephone
38a.
[0103] Because of this, in the case where a terminal that performs
communication is a telephone, an audio, a character, and a video
are relayed by priority in this order. This is because, in the
communication by a telephone, the transmission of an audio is
important in most cases. Furthermore, for example, in the case of
transmitting an image of a monitoring camera, or the like, the
transmission of a video is more important than that of an audio.
Therefore, the priority of a video can be set to be higher than
that of an audio, as in the multimedia priority table for a camera
38b. Thus, by providing a multimedia priority table for each
terminal type, the priority of multimedia types can be changed
depending upon the type of a terminal that is ready to start
communication.
(Method for Setting a Predetermined Required Available
Bandwidth)
[0104] Herein, a modified example of the processing will be
described in which an upper limit value used for obtaining a usable
bandwidth is determined after the updating part 8 obtains the
bandwidth in use (#803b) in the processing shown in FIG. 6 will be
described. The upper limit value is a maximum value of a bandwidth
that can be allocated to communication to be relayed by priority.
The difference between the upper limit value and the bandwidth in
use is a usable bandwidth. In the present modified example, as an
example, the updating part 8 obtains the upper limit value by the
following expression.
Upper limit value=Maximum value of a bandwidth that can be used
by the AP 1a for wireless communication-Required Available
Bandwidth
[0105] Herein, the required available bandwidth is a bandwidth
required to be left without being allocated to the communication to
be relayed by priority, among the bandwidths that can be used by
the AP 1a for wireless communication. By leaving an available
bandwidth at all times, a bandwidth can be always allocated to the
communication other than the communication to be relayed by
priority. In the present modified example, a required available
bandwidth uses a value varied depending upon a required bandwidth
required for relaying communication ready to be started.
[0106] For example, in the case where it is desired to allocate a
certain number or more audio communications, the following setting
is performed. The updating part 8 can determine a required
available bandwidth with reference to a required available
bandwidth table 41 as shown in FIG. 12. The required available
bandwidth table 41 stores data representing a range of a required
bandwidth required for relaying communication ready to be started
and data representing a required available bandwidth so that they
are associated with each other. In the example shown in FIG. 12, in
the case where the required bandwidth is 200 or less, the required
available bandwidth is equal to a required bandwidth. The required
available bandwidth in the case where the required bandwidth is 201
to 400 is set to be 800, the required available bandwidth in the
case where the required bandwidth is 401 to 800 is set to be 1600,
and the required available bandwidth in the case where the required
bandwidth is 801 or more is set to be 128.times.average number of
telephone conversations. As the average number of telephone
conversations, the average value of the number of telephone
conversations relayed by the AP on a daily basis is used.
[0107] The updating part 8 uses the required available table 41 as
shown in FIG. 12, thereby increasing the required available
bandwidth as the required bandwidth is larger. For example, the
communication including a video with a large required bandwidth,
and the like as multimedia types can be set so as not to be relayed
by priority, if there is no large available bandwidth. Because of
this, the available bandwidth of the AP can be prevented from being
occupied by a small number of communications that use a large
bandwidth.
[0108] In the above embodiment, the case has been described in
which a communication control apparatus that controls the
communication of a wireless terminal is an SIP server. However, the
communication control apparatus is not limited to the SIP server,
and may be a communication control apparatus that starts/ends the
communication between terminals in a network. Furthermore, as an
operation example, an exemplary case has been described in which
the wireless terminals start/end the communication of an audio and
a video. However, the communication relayed by the AP is not
limited to that between wireless terminals. For example, even in
the case where the communication between a wireless terminal and a
server connected to a wired network is started, the bandwidth of
the communication can be allocated for each multimedia type in the
AP.
Embodiment 2
[0109] In Embodiment 1, the selecting part 9 selects some of a
plurality of streams included in communication in accordance with a
multimedia type. In Embodiment 2, regarding a plurality of streams
included in communication, the priority of communication quality of
each stream is varied depending upon a multimedia type.
[0110] FIG. 13 is a functional block diagram showing a detailed
configuration of an AP 10a in Embodiment 2. In FIG. 13, the same
functional blocks as those in FIG. 2 are denoted with the same
reference numerals as those therein, and the description thereof
will be omitted.
[0111] The AP 10a shown in FIG. 13 includes a priority grade data
recording part 16 instead of the priority data recording part 13
shown in FIG. 2. Furthermore, the AP 10a includes a priority
determining part 12 instead of the selecting part 9 shown in FIG.
2.
[0112] A plurality of the priority grade data recording parts 16
are provided for respective stages of priorities in a plurality of
stages. Each priority grade data recording part 16 stores stream
identification data for identifying a stream to be relayed by
priority, and required bandwidth data representing a bandwidth
required for relaying the stream by priority.
[0113] FIG. 14 shows a specific example of data recorded in each
priority grade data recording part 16 provided for each priority.
FIG. 14 shows a first priority table representing an example of
data recorded in the priority grade data recording part 16 with a
priority of "1", and a second priority table representing an
example of data recorded in the priority grade data recording part
16 with a priority of "2". The first priority table 39a and the
second priority table 39b store data representing a source IP
address, a destination IP address, a port number, a state, and a
required bandwidth so that they are associated with each other for
each stream to be relayed by priority.
[0114] The source IP address, the destination IP address, and the
port number are one exemplary stream identification data
representing a stream to be relayed by priority. The stream relayed
by priority is specified by the source IP address, the destination
IP address, and the port number. The state is data representing the
communication state of the stream represented by the stream
identification data. The required bandwidth is data representing a
bandwidth required for relaying the stream specified by the stream
identification data (the source IP address, the destination IP
address, and the port number).
[0115] FIG. 14 shows the case where the priority grade data
recording parts 16 are provided with respect to two stages of the
priorities of "1" and "2"; however, the priority is not limited two
stages. Furthermore, the stream identification data is not limited
to the source IP address, the destination IP address, and the port
number.
[0116] A priority control part 15a controls the wireless LAN
interface 17 and allows it to relay the communication of a stream
specified by the communication identification data and the
multimedia identification data recorded in the priority grade data
recording part 16 with higher priority, by further priority
compared with the communication of a stream represented by the
communication identification data recorded in the priority grade
data recording part 16 with lower priority, among a plurality of
priority grade data recording parts 16. For example, the priority
control part 15a allows the stream specified by the source IP
address, the destination IP address, and the port number recorded
in the first table shown in FIG. 14 to be relayed by further
priority compared with the stream specified by the source IP
address and the destination IP address port number recorded in the
second priority table.
[0117] The request receiving part 7 receives a request for
relaying, by priority, the communication of a wireless terminal
ready to be started from the interconnecting part 21 of the SIP
server 2. At this time, the request receiving part 7 receives
communication identification data representing communication to be
relayed by priority and multimedia based data representing
multimedia types of one or a plurality of streams.
[0118] The priority determining part 12 determines the priority
regarding a stream of each multimedia type represented by the
multimedia type data received by the request receiving part 7,
based on the precedence recorded in the precedence recording part
11.
[0119] The updating part 8 records the stream identification data,
the state, and the required bandwidth data in the priority grade
data recording part 16 in accordance with the priority determined
by the priority determining part 12, regarding a stream of each
multimedia type represented by the multimedia type data. A
responding part 14a transmits a response to the request received by
the request receiving part 7 to the SIP server 2.
[0120] Next, the operation example of the wireless communication
system in the present embodiment in the case where communication by
wireless terminals is performed will be described. The processing
flow of the entire wireless communication system in the case where
communication by the wireless terminals is performed is the same as
that shown in FIG. 5.
[0121] FIG. 15 is a sequence diagram showing an example of the
processing when a request for bandwidth reservation is transmitted
from the SIP server 2 to the AP 10a in #8 shown in FIG. 5. More
specifically, the processing shown in FIG. 15 is an example of the
processing in the case where the SIP server 2 having received an
INVITE message requesting the starting of communication from the
wireless terminal 3a requests the AP 10a to reserve bandwidth
allocation for the communication. In the processing shown in FIG.
15, the same processing as that shown in FIG. 6 is denoted with the
same reference numerals as those therein, and the description
thereof will be omitted.
[0122] In FIG. 15, the processings in #8 to #802 are the same as
those shown in FIG. 6. In #8031a, an updating part 8a requests the
priority determining part 12 to determine the priority of a stream
to be relayed by priority. For example, in the case where the
updating part 8a has received an audio and a video as multimedia
types of streams included in communication from the request
receiving part 7, the updating part 8a requests the priority
determining part 12 to determine the priority of an audio and the
priority of a video. The priority determining part 12 refers to the
precedence recording part 11 (#8041a), and obtains the priority of
a multimedia type for each stream included in communication
(#8041b).
[0123] The priority determining part 12 determines the priority of
a stream for each multimedia type based on the obtained priority
(#8051). For example, in the case where the data recorded in the
precedence recording part 11 is the multimedia priority table 32
shown in FIG. 4, and the multimedia types of streams included in
the communication are an audio and a video, the priority
determining part 12 determines the priority of an audio to be "1"
and the priority of a video to be "2". The priority determining
part 12 notifies the updating part 8a of the determined priority
(#8031b).
[0124] The updating part 8a refers to the priority grade data
recording part 16 provided for each priority in a plurality of
stages (#8061a), thereby obtaining a bandwidth that is being used
by the stream to be relayed by priority or a bandwidth to be used,
regarding the respective priorities in plurality of stages
(#8061b). For example, the updating part 8a obtains, as a bandwidth
of the communication with the priority of "1", the sum
(128+420+128=676) of bandwidths represented by the required
bandwidth data recorded in the first priority table 39a shown in
FIG. 14. Furthermore, the updating part 8a obtains, as a bandwidth
of the communication with the priority of "2", the sum
(128+128=256) of the bandwidths represented by the required
bandwidth data recorded in the second priority table 39b.
[0125] When the updating part 8a has obtained the bandwidth for
each priority, the updating part 8a calculates a usable bandwidth
for each priority, using the obtained bandwidth in use. The usable
bandwidth is obtained, for example, based on the difference between
the bandwidth in use of each priority and a predetermined upper
limit value. Herein, the predetermined upper limit value may be
varied depending upon each priority, or may be the same.
[0126] For example, in the case where the bandwidth of the
communication with the priority of "1" is 676, and the
predetermined upper limit value with the priority of "1" is 1000,
the bandwidth of the communication with the priority of "1" becomes
1000-676=324. Furthermore, in the case where the bandwidth of the
communication with the priority of "2", and the predetermined upper
limit value with the priority of "2" is 1000, the usable bandwidth
of the communication with the priority of "2" becomes
1000-256=744.
[0127] The updating part 8a having obtained the usable bandwidth
for each priority compares the usable bandwidth of each priority
with the required bandwidth of a stream of a multimedia type having
a corresponding priority. If the bandwidth in use is large, the
updating part 8a records the stream identification data, the state,
and the required bandwidth of the corresponding multimedia type in
the priority grade data recording part 16 with that priority.
[0128] For example, in the case where the priority of an audio is
"1", and the priority of a video is "2", the updating part 8a
compares the usable bandwidth of the communication with the
priority of "1" with the required bandwidth of an audio stream. If
the usable bandwidth is larger, the updating part 8a registers
information regarding the audio stream in the first priority table
39a of the priority of "1". The updating part 8a compares the
usable bandwidth of the communication with the priority of "2" with
the required bandwidth, regarding a video stream. If the usable
bandwidth is larger, the updating part 8a records data regarding
the stream in the first priority table 39a of the priority of "1".
Thus, bandwidth allocation is reserved (#8071a).
[0129] In the above example, the audio stream is relayed by
priority, and the video stream is relayed to a wireless terminal
although the relay priority is lower than that of the audio.
Therefore, the video stream is relayed even in slightly delay from
the audio stream. Thus, at the wireless terminal, first, a required
audio is relayed by priority, whereby at least conversation can be
performed smoothly even with the degradation in quality and the
delay of a video.
[0130] In the case where the usable bandwidth is smaller than the
required bandwidth, the allocation of a bandwidth may be reserved
for each priority of a multimedia type, or bandwidths may be
allocated in stages as follows.
[0131] More specifically, in a certain priority, in the case where
the required bandwidth required for relaying a stream exceeds the
usable bandwidth, the updating part 8a compares the required
bandwidth required for relaying a stream of that priority with the
usable bandwidth at a priority lower by one stage. If the required
bandwidth does not exceed the usable bandwidth of a priority lower
by one stage, bandwidth is reserved with that priority. Because of
this, for example, even if the stream of a multimedia type
determined to be the priority of "1" in the priority determining
part 12 has not been reserved for bandwidth allocation due to the
shortage of a bandwidth in the first priority table 39a of the
priority of "1", there is a possibility that bandwidth allocation
may be reserved in the second priority table 39b of the priority
"2". Thus, by comparing the required bandwidth with the usable
bandwidth by decreasing the priority by one stage until bandwidth
allocation is reserved, the priority that can be reserved is
determined.
[0132] The stream identification data of a stream that cannot be
reserved even by decreasing the priority to a lowest level, i.e., a
stream that cannot be recorded even in the priority grade data
recording part 16 of any priority may be recorded in, for example,
a separately provided non-priority table. The priority control part
15 can ensure the relay although it does not relay, by priority,
the stream of stream identification data recorded in a non-priority
table. Because of this, the communication of a stream can be
started under the condition that the relay is ensured while the
quality of communication is not ensured.
[0133] When bandwidth allocation is reserved, and the updating part
8a has received the notification of the completion of data
recording (#8071b), the updating part 8a notifies the responding
part 14a that the bandwidth allocation has been reserved (#8081).
The responding part 14a transmits an OK message to the
interconnecting part 21 of the SIP server 2. The interconnecting
part 21 receives an OK message as a response to the request for
bandwidth reservation (#9). Because of this, the SIP server 2 can
obtain a response showing that a bandwidth can be allocated by the
AP 1a.
[0134] The processing shown in FIG. 15 is an example, and the
processing of reserving bandwidth allocation by the AP is not
limited to the example shown in FIG. 15. The updating part 8a
determines, for example, whether or not both the stream of the
multimedia type whose priority is determined to be "1" by the
priority determining part 12 and the stream of the multimedia type
whose priority is determined to be "2" can be recorded in the first
priority table 39a of the priority of "1". In the case where both
of them cannot be recorded, the stream of the multimedia type with
a priority of "2" may be recorded in the second priority table.
Embodiment 3
[0135] FIG. 16 is a functional block diagram showing a detailed
configuration of an AP 100a according to Embodiment 3. In FIG. 16,
the same functional blocks as those in FIG. 2 are denoted with the
same reference numerals as those therein, and the description
thereof will be omitted. The AP 100a shown in FIG. 16 does not have
the precedence recording part 11 as shown in FIG. 2. A selecting
part 9b shown in FIG. 16 requests a SIP server 2 to inquire of a
wireless terminal that is ready to start communication about the
multimedia type of a stream to be relayed by priority, instead of
referring to the precedence recording part 11. The selecting part
9b receives, as a response from the SIP server 2, the data
representing the multimedia type of a stream to be relayed by
priority, and selects a multimedia type of a stream to be relayed
by priority based on the received data.
[0136] FIG. 17 is a sequence diagram showing an example of the
processing in which a request for bandwidth reservation is
transmitted from the SIP server 2 to the AP 100a in #8 shown in
FIG. 5. In the processing shown in FIG. 17, the same processings as
those shown in FIG. 6 are denoted with the same reference numerals
as those therein, and the description thereof will be omitted.
[0137] In FIG. 17, the processings from #8 to #804a are the same as
those shown in FIG. 6. In #8042a, the selecting part 9b requests
the interconnecting part 21 of the SIP server 2 to inquire of the
wireless terminal that is ready to start communication about a
multimedia type. The SIP server 2 inquires of the wireless terminal
3a about the multimedia type of a stream to be relayed by priority.
The wireless terminal 3a notifies the SIP server 2 of the data
representing the multimedia type of a stream to be relayed by
priority. The interconnecting part 21 of the SIP server 2 transmits
the data representing the multimedia type of a stream to be relayed
by priority to the selecting part 9b of the AP 100a. The selecting
part 9b receives, as a response to the inquiry, the data
representing the multimedia type of a stream to be relayed by
priority (#8042b). The selecting part 9b selects the multimedia
type based on the multimedia type of the received stream
(#8061).
[0138] For example, the case will be described in which the
multimedia types of streams included in communication ready to be
started are an audio and a video, and the multimedia type: the
required bandwidth of an audio is 128 and the multimedia type: the
required bandwidth of a video is 420. It is assumed that a usable
bandwidth is, for example, 450. In this case, although the sum of
the required bandwidths of an audio and a video exceeds the usable
bandwidth, the required bandwidth of either one of them does not
exceed the usable bandwidth. The selecting part 9b transmits a
message that inquires of the wireless terminal 3a about which of an
audio or a video is relayed by priority to the interconnecting part
21 of the SIP server 2. The selecting part 9b receives, as a
response to the inquiry, for example, the data representing the
multimedia type in which the data representing an audio is relayed
by priority. In this case, the selecting part 9b selects an
audio.
[0139] Thus, by inquiring of the wireless terminal 3a that is ready
to start communication about the multimedia type to be relayed by
priority, the multimedia type of a stream to be relayed by priority
can be selected, considering the indication of a user of the
wireless terminal 3a.
[0140] In the present embodiment, the example has been described in
which the selecting part 9b inquires of the wireless terminal about
the stream to be relayed by priority, instead of referring to the
precedence recording part 11. The selecting part 9b may select a
stream with a small required bandwidth by priority, as another
processing replacing the processing of referring to the precedence
recording part 11.
[0141] As described above, in Embodiments 1 to 3, as an example,
the configuration and the operation of an AP for a wireless LAN
have been described. The wireless LAN is a specification of a short
distance wireless network determined by IEEE 802.11. However, the
relay apparatus of the present invention is not limited to an AP
for a wireless LAN. For example, the relay apparatus of the present
invention can also be applied to the AP for a wireless MAN that is
a specification of a long distance wireless network determined by
WiMAX.
[0142] The present invention can be used as a relay apparatus, a
relay method, a relay program, and a communication system capable
of performing bandwidth control of communication to be relayed
considering a multimedia included in communication by a wireless
terminal.
[0143] The invention may be embodied in other forms without
departing from the spirit or essential characteristics thereof. The
embodiments disclosed in this application are to be considered in
all respects as illustrative and not limiting. The scope of the
invention is indicated by the appended claims rather than by the
foregoing description, and all changes which come within the
meaning and range of equivalency of the claims are intended to be
embraced therein.
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